One of the side effects of serious illness is a sudden drop in the level of tact to which the sick person is exposed.

You might suppose that those who are sensitive enough to show concern for the afflictions of others would have the sensitivity not to contribute to their discomfort. Miss Manners is sorry to report that you would be wrong.

Illness often brings out the worst in the well. They accost strangers. They point out physical symptoms. They ask nosy questions. They offer unsolicited and unsubstantiated medical and physiological advice. They relate tales of others with the same or a similar disease to make the point that miraculous recoveries should be expected. Or they relate such tales to make the point that there are much worse cases, which the person they are addressing should feel lucky not to have.

Why do they do keep doing this sort of thing?

They'll tell you why. It's because they care. And because they want to cheer up the sick.

These are noble motives, and Miss Manners does not doubt that some of the people who claim to harbor them actually do care. It all goes to show that good feelings can be bad guides to good behavior.

Two of the most natural reactions to serious illness are curiosity and fear, and these are the ones that prompt the worst behavior. The curious fire off questions that not only invade the privacy of the ill but keep them conversationally confined to that one topic. The fearful just shun them. Both kinds defend themselves on the basis of their own emotions ("I was just curious" or "I can't stand to see him like that") without so much as considering the emotions that their behavior is apt to cause.

This makes it difficult for Miss Manners to count them among the caring. But even those who do care, to greater or lesser degrees, are mistaken if they believe that they can always depend on the simple and direct expression of their feelings to make anyone feel better. Other than themselves, that is.

They have to learn to gear their expressions of concern to their general knowledge of the sick person and on-the-spot assessments of that person's mood at a given time. Even inquiries about someone's immediate state of health can be annoying if they are too frequent, or if they come at a time when that person was feeling chipper enough to concentrate on something else and didn't need to be reminded.

Discussions of the disease should be initiated -- or not -- by the person who has it. Miss Manners has never yet heard such a person beg someone who neither has nor treats the disease to cough up every scrap he has heard about it and every case history he knows, but these should not be offered without an invitation.

Those overdue calls that people make on hearing bad news can be welcome or depressing. The ones that take the tone of "I miss you" are usually welcome. The ones that take the tone of "I figured I'd better call before I miss you" are not.

A question sympathizers might ask themselves is not only how the sick person feels now, deeply as they may worry about this, but how that person will feel after their concern has been expressed.

Dear Miss Manners:

I am recently divorced after 21 years. Family and friends have come up to me many times and have said, "We never liked him. Did you know that?" They may have thought they were trying to make me feel better, but I assure you, it hurt and still does. I consider it an insult. What can I say to them that will stop them dead in their tracks?

"Well, I did." And, presuming that you can reasonably add this, "as a matter of fact, I still do."

Miss Manners understands how galling it is to be told that people with whom you socialized were secretly disparaging your spouse all along, even when things were going well. Makes you wonder about their opinion of you, beginning with how naive you were not to see his undesirability when they did.

Feeling incorrect? E-mail your etiquette questions to Miss Manners (who is distraught that she cannot reply personally) at MissManners@unitedmedia.com or mail to United Media, 200 Madison Ave., New York, N.Y. 10016.

(c) 2004, Judith Martin